The present invention relates to a new and improved method of, and apparatus for, fabricating a substantially U-shaped body, especially a bifurcated or fork-type joint for a Cardan or universal joint from a blank or unfinished part, which is worked by cold impact or press forming while using dies and punches.
Different techniques are known in the art for fabricating a U-shaped body. In particular, such bodies are forged from one piece. This is associated with the drawback that the body subsequently must be heat-treated or tempered and there is required considerable material-removing finishing work, for instance it is necessary to subsequently carry out face milling and drilling operations.
Also, it is known to stamp such type bodies from sheet metal. Yet, this is associated with the drawback that the body does not possess adequate rigidity for many fields of application.
Additionally, it is also known to fabricate such bodies from two parts which are subsequently welded together. This, however, is associated with the disadvantage that the welding operation requires a relatively large amount of work.
Finally, it is also part of the state-of-the-art to fabricate such type bodies by cold impact or press forming techniques, for instance, as disclosed in U.S. Pat. Nos. 1,925,721 and 2,120,118. However, with these techniques the forming work is maintained as small as possible, so that equally the strength which is achieved by such cold working is relatively small. Moreover, splitting of the blank for forming both legs or leg members is associated with the disadvantage that there are formed sharp edges requiring a further machining operation.